Have you ever noticed that different sounds distract your German Shepherd's attention from training? It prevents him to follow your commands?
You are not alone. This problem is not a new one.
This Bamboo Dog Stick is a solution you are looking for. This working dog equipment is intended to make noise while training process. An assistant should use this supply while a trainer do his work. In this way dog will get used not to pay attention to sounds around and will be more concentrated on commands of the trainer.

Noise Making German Shepherd Stick of Bamboo
This Noise Making Stick is made of bamboo, safe natural material. This dog training equipment has handle part that is covered with a tape. It allows to hold the stick reliably in the hand.

Bamboo German Shepherd Stick with Tape Covered Handle
Take a look at training stick in 3D